Thanks for the replies so far.

A little more info.

1. I didn't measure CYA because I was out of the regents I need. I'll try to get a measurement tonight.
2. I don't remember if I closed with a high chlorine level. I did use chlorine-free shock when I closed.
3. I shocked with chlorine (bleach) when I opened.
4. I also tried crushed up vitamin C in a sock-- didn't seem to make a difference.
5. Checked my log... Calcium was at 350 when I closed.

Pat.